Alexsandra Cristina Chaves

Oil Well Cement Developed from Common Cement: Physical, Chemical and Mineral Characterization

This study aims to characterize a new type of cement, produced from the mixture of common Portland cements, which could be used as an option in the cementing of oil wells. To enable this study a linear programming method was used for the composition of the new cement, then, characterization tests were performed through particle size analysis by laser diffraction, chemical analysis by EDX, thermogravimetric analysis, X-ray diffraction, setting time, compressive strength. The results allowed the conclusion that the new formulated cement presented low C3A content, time setting superior to the Portland Cement for Oil Well, thermal stability up to 500 °C, low hydration kinetics and content of the main components coherent to the ABNT specifications.

Use of the Processed Waste from Kaolin and Granite Sawing in the Manufacture of Tubular Ceramic Membranes

The incorporation of waste from various industrial activities in ceramic products comes as a technological alternative to reduce the environmental impacts caused by the indiscriminate disposal of wastes in the environment. The kaolin and granite processing industries have been mentioned as sources of contamination and pollution, due to the enormous amounts of wastes they produce. The use of these wastes as raw material and its transformation into products that can be commercialized and/or show economic viability, presents as an alternative to the industries. The aim of this work was to use ceramic masses incorporated with kaolin waste (35%), granite (35%) and bentonite (30%) for the confection of tubular ceramic membranes using extrusion as production process. The ceramic mass was characterized through analysis techniques of thermogravimetric, chemical, particle size and X-ray. The membranes produced, after sintering in temperatures of 850, 900, 950 and 1000 oC, were submitted to characterizations of scanning electron microscopy, mercury porosimetry and permeability test by tangential flow. The preliminary result of the particle size analyses identified that the ceramic mass presents an average particle diameter of 37.00μm. The membranes presented porosity of approximately 32%, and average pore diameter within the ultrafiltration range.

Obtenção e caracterização de membranas cerâmicas tubulares a partir de massas incorporadas com argila, caulim e quartzo

The technology that involves the use of ceramic membranes has become in the last decades an important separation technique. The main reasons in the advance of this technology are related to the fact that work without addition of chemical reagents, low consumption of energy, ease to processing and compact physical arrangements. Today the main concern in the development of these membranes is to minimize the costs and more efficient production processing. In this way the use of natural raw materials comes as an alternative to prepare ceramic membrane, using extrusion as processing technique. The aim of this work is to study the use of natural raw materials, such as, clay, quartz and kaolin to prepare tubular ceramic membranes in laboratorial scale using extrusion processing. The ceramic mass was submitted to characterizations: physical and mineralogical through particle size, thermogravimetry, X-ray diffraction and X-ray fluorescence analysis. The samples were sintered at temperatures of 800, 900, 1000 and 1100 oC, with the aim to verify the influence on membrane characteristics. Ceramic membranes were characterized by scanning electron microscopy and mercury porosimetry, were it was possible to verify the absence of defects and cracks in its structure. In relation to the porosimetry analysis, pores in the range of ultra-filtration were observed.

Characterization of Kaolin Residues from the Jarí Valley Reservations Provided by Cadam S/A Company

The ceramic industry is one of the most important productive chains of the State of Pará, generating both money and employment. Kaolin has many industrial applications and new uses are constantly surveyed. Although the extraction and processing of kaolin contribute to the economy growth, the activity also provokes serious environmental issues. Being aware of the environmental problem caused by the inadequate decomposition of kaolin residues from the beneficiation process of these minerals, which pollute and attack the environment, this paper aims the chemical, physical and mineralogical characterization of the kaolin residue from the post-treatment disposal provided by CADAM S/A company. The main oxides in the residues were SiO2 and Al2O3. In the X-ray diffraction analysis it was verified that the kaolin residue is basically formed by kaolinite and quartz, in the particle size analysis it was observed that the medium size of the particle was of 1,77 μm.

Influence of Oxidizing Atmosphere on Crystalline Phase Formation and Microstructural Properties of Mixed Cerium-Zinc Oxides Obtained by Polymeric Precursor Method

This paper presents the synthesis, characterization and influence of oxidizing atmosphere in the calcinations and sintering processes on microstructural properties of mixed oxides of Cerium and Zinc, obtained by the polymeric precursor method, aiming at a subsequent catalytic application. The material was submitted to calcinations and sintering at 900 and 1050 °C. The samples were characterized by XRD analysis techniques, surface area by BET method and refined by the Rietveld method. The results of X-ray diffraction showed that interest phase was formed, indicating that the method for obtaining the phase is effective. The results of surface area for the system calcined in air were 85 m2/g and 65 m2/g for the system subjected to oxidizing atmosphere both at 900°C, in the same temperature. It was observed that the temperature increase leads to an increase in crystallite size. This fact is in line with other studies in the literature.

Portland Cement for the Cementing of Oil Wells Developed with the Aid of the Rietveld Refinement Method

The use of the Rietveld refinement method has been highlightened as essential in the characterization of polycrystalline materials. With the aid of this method, combined with the application of the X-ray diffraction, it was possible to develop a type of cement that can temporarily substitute the Portland cement for Oil well. This cement was developed from the mixture of Portland cements commonly found in the market. The cements were passed through various sieves, then characterized by X-ray diffraction, being identified the main phases (C3A, C4AF, C3S and C2S) and quantified by the Rietveld refinement method. With the values obtained in the quantification of the phases, a new cement was made through the method of linear programming. From the results, it was possible to conclude that the developed cement presented a composition (levels of the main phases) that satisfies the requirements of NBR 9831, mainly in relation to the low levels of C3A.

Characterization and Study of the Moisture Expansion of Ceramic Blocks from Ceramic Masses Incorporated with Kaolin and Granite Wastes

The study of moisture expansion (ME) in ceramic products has been object of research in the past few years, especially in UFCG. The ME is the increase of the dimensions of the ceramic materials by adsorption of water, it occurs slowly and is relatively small, being able to compromise the adherence of the ceramic plates to the subfloor, lead to the cracking of the glaze and conduct to the appearance of cracks in bricks, if the tensions generated by the deformation contained in the pieces exceed the limit resistance of the materials. Aiming to contribute with this research, this study aimed to characterize the alternative ceramic masses from ceramic blocks, seeking to determinate their influence in the development of the moisture expansion phenomenon. Compositions were formulated through the design of simplexes network mixtures technique. The specimens were conformed by uniaxial pressing at 20 MPa, dried in an oven at 110 °C and fired at temperatures of 800°, 900° and 1000 °C. After firing the MEs were determined by boiling and immersion. The results showed that the higher the percentage of granite waste in the formulation, lower the ME.

Particle Size Study of Smectite Clays from the City of Pedra Lavrada-PB

The state of Paraíba disposes of one of the largest deposits of smectites in the country. However, these smectites present in their composition elevated contents of accessory minerals, especially quartz. For these clays to become viable to determine technological use it is necessary the elimination of part of these minerals. The particle size analysis of a soil consists in the determination of the size of the particles that constitute it and their distribution in certain intervals. This work aims to study smectite clays from the city of Pedra Lavrada-PB, through the particle size analyses, for the use in water based drilling fluids. The determination of particle size was made by sieving and laser granulometer. Apparent and plastic viscosities were measured from the samples. The clays were left at rest before the test for periods of 7 and 28 days, with and without deflocculant. It was verified that there was no significant difference in the particle sizes in relation to the resting time of the samples.

Evaluation of the Thermal Stability of Biofuel Obtained from Oil Plant Pyrolysis and Animal Fat

The present study reports obtaining biofuel by pyrolysis of plant oil and animal fat. This process consists in breaking of molecules at high temperatures, obtaining hydrocarbons, similar to oil, and oxygenates such as esters, carboxylic acids, aldehydes, etc. The research aimed to evaluate the thermal and kinetic behaviour and the heat of combustion of bio-oil and bio-oil mixtures / diesel oil. In this work, Thermogravimetric studies were performed (TG) at a heating rate of 10 ° C min-1 under air atmosphere synthetic, Thermodynamic studies (ΔH, ΔS and ΔG) and about heat of combustion also were done. Thermal stability at 30°C was observed from thermogravimetric study. The kinetic calculations were performed in order to observe parameters such as activation energy (Ea) and Arrhenius factor.

Employment of Response Surface Methodology for Optimization of the Portland Cement Mechanical Resistance

For this workmixtureswere madewith three types ofPortland cement (CPII,CPIII, and CPIV), which were chosen because theyexhibit: good mechanical properties,lower heat ofhydrationgeneratedin the reaction, greater impermeability, greater resistance to environmentsaggressive.The objectwas to improve themechanical strengthofcementpasteswith the helpof experimental design. Ten different compositionswere prepared, which were tested forcompressivestrengthat 1 and14 days ofcuring. The results illustrated that the first day; the composition showed that the best result was composed of 50% of CP II and 50% of CP III. Already at 14 days, a paste made with 100% of CP III showed better results followed by composition made with 50%CP II and CP III 50%.